Chimney Swift

The Chimney Swift is a small, sooty gray-brown bird built almost entirely for life in the air—a stubby, cigar-shaped body, long narrow wings that appear stiffly bowed in flight, and a very short, squared tail. It never perches in the open the way most birds do; its tiny feet are suited only for clinging vertically to rough surfaces inside chimneys or hollow trees.

Once dependent on hollow trees for nesting and roosting, the species adapted readily to masonry chimneys as European settlement spread across eastern North America, giving rise to its common name. Large numbers can be seen swirling into chimneys at dusk during migration, a spectacle that draws birdwatchers to urban roost sites.

Key field marks

• Small, dark, cigar-shaped silhouette
• Long, narrow, stiffly bowed wings
• Very short, square tail
• Never perches in the open; always seen flying or clinging inside a chimney

Similar species

• Vaux's Swift: very similar but smaller, paler on the throat and rump, and largely restricted to the West; ranges barely overlap.
• Swallows: have broader-based wings, notched or forked tails, and often perch on wires, unlike swifts.

Range and habitat

Chimney Swift breeds across the eastern United States and southeastern Canada, wherever chimneys, hollow trees, or similar vertical structures are available for nesting and roosting. It forages over towns, cities, farmland, and forest openings.

Migration

A long-distance migrant, wintering in the upper Amazon basin of Peru and Brazil—a wintering area only confirmed relatively recently through band recoveries.

Behavior

Spends nearly all of its waking hours in flight, foraging, drinking, and even gathering nest material on the wing; it clings to vertical surfaces to roost and nest but cannot perch like a typical bird.

Voice

A rapid, chattering series of high, ticking twitters given in flight.

Feeding

Catches flying insects exclusively on the wing, often foraging at considerable heights.

Nesting and breeding

Builds a small half-saucer nest of twigs glued together and to the chimney wall with the bird's own sticky saliva. The female incubates 3-5 eggs for about 3 weeks; large numbers roost communally in chimneys during migration.